We claim the ornamental design for a vacancy sensor, as shown and described.

Descripción

FIG. 1 is a perspective view of a vacancy sensor according to a first embodiment of our new design.

FIG. 2 is a front view thereof.

FIG. 3 is a left side view thereof.

FIG. 4 is a right side view thereof.

FIG. 5 is a top view thereof.

FIG. 6 is a bottom view thereof.

FIG. 7 is a perspective view of a dimmer switch according to a second embodiment of our new design.

FIG. 8 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the second embodiment being identical to the left side, right side, top, and bottom views of the first embodiment.

FIG. 9 is a perspective view of a vacancy sensor according to a third embodiment of our new design.

FIG. 10 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the third embodiment being identical to the left side, right side, top, and bottom views of the first embodiment.

FIG. 11 is a perspective view of a vacancy sensor according to a fourth embodiment of our new design.

FIG. 12 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the fourth embodiment being identical to the left side, right side, top, and bottom views of the first embodiment.

FIG. 13 is a perspective view of a vacancy sensor according to a fifth embodiment of our new design.

FIG. 14 is a front view thereof.

FIG. 15 is a top view thereof.

FIG. 16 is a bottom view thereof, the left side and right side views, respectively, of the fifth embodiment being identical to the left side and right side views of the first embodiment.

FIG. 17 is a perspective view of a vacancy sensor according to a sixth embodiment of our new design.

FIG. 18 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the sixth embodiment being identical to the left side, right side, top, and bottom views of the fifth embodiment.

FIG. 19 is a perspective view of a vacancy sensor according to a seventh embodiment of our new design.

FIG. 20 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the seventh embodiment being identical to the left side, right side, top, and bottom views of the fifth embodiment.

FIG. 21 is a perspective view of a vacancy sensor according to an eighth embodiment of our new design.

FIG. 22 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the eighth embodiment being identical to the left side, right side, top, and bottom views of the fifth embodiment.

FIG. 23 is a perspective view of a vacancy sensor according to a ninth embodiment of our new design.

FIG. 24 is a front view thereof.

FIG. 25 is a left side view thereof.

FIG. 26 is a right side view thereof.

FIG. 27 is a top view thereof.

FIG. 28 is a bottom view thereof.

FIG. 29 is a perspective view of a dimmer switch according to a tenth embodiment of our new design.

FIG. 30 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the tenth embodiment being identical to the left side, right side, top, and bottom views of the ninth embodiment.

FIG. 31 is a perspective view of a vacancy sensor according to an eleventh embodiment of our new design.

FIG. 32 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the eleventh embodiment being identical to the left side, right side, top, and bottom views of the ninth embodiment.

FIG. 33 is a perspective view of a vacancy sensor according to a twelfth embodiment of our new design.

FIG. 34 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the twelfth embodiment being identical to the left side, right side, top, and bottom views of the ninth embodiment.

FIG. 35 is a perspective view of a vacancy sensor according to a thirteenth embodiment of our new design.

FIG. 36 is a front view thereof.

FIG. 37 is a top view thereof.

FIG. 38 is a bottom view thereof, the left side and right side views, respectively, of the thirteenth embodiment being identical to the left side and right side views of the ninth embodiment.

FIG. 39 is a perspective view of a vacancy sensor according to a fourteenth embodiment of our new design.

FIG. 40 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the fourteenth embodiment being identical to the left side, right side, top, and bottom views of the thirteenth embodiment.

FIG. 41 is a perspective view of a vacancy sensor according to a fifteenth embodiment of our new design.

FIG. 42 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the fifteenth embodiment being identical to the left side, right side, top, and bottom views of the thirteenth embodiment.

FIG. 43 is a perspective view of a vacancy sensor according to a sixteenth embodiment of our new design; and,

FIG. 44 is a front view thereof, the left side, right side, top, and bottom views, respectively, of the sixteenth embodiment being identical to the left side, right side, top, and bottom views of the thirteenth embodiment.

The rear views form no part of the design and are omitted. The portions of the drawings appearing in broken line are for environment only and do not form a part of the claimed design.